package main

// 类型断言 x.(T)
import "fmt"

func assert(a interface{}){
	fmt.Printf("%T\n",a)
	v,ok := a.(string)
	if !ok {
		fmt.Println("NO string")
	}else{
		fmt.Println("this is string:",v)
	}
}
func main()  {
	assert("zhihuan")
	assert(123)
}